[PATCH 1/4] PCI/sysfs: Add pci_dev_resource_attr_is_visible() helper

["Krzysztof Wilczyński" <kw@linux.com>]

This helper aims to replace functions pci_create_resource_files() and
pci_create_attr() that are currently involved in the PCI resource sysfs
objects dynamic creation and set up once the.

After the conversion to use static sysfs objects when exposing the PCI
BAR address space this helper is to be called from the .is_bin_visible()
callback for each of the PCI resources attributes.

Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
---
 drivers/pci/pci-sysfs.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index b70f61fbcd4b..c94ab9830932 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1237,6 +1237,46 @@ static int pci_create_resource_files(struct pci_dev *pdev)
 	}
 	return 0;
 }
+
+static umode_t pci_dev_resource_attr_is_visible(struct kobject *kobj,
+						struct bin_attribute *attr,
+						int bar, bool write_combine)
+{
+	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+	resource_size_t resource_size = pci_resource_len(pdev, bar);
+	unsigned long flags = pci_resource_flags(pdev, bar);
+
+	if (!resource_size)
+		return 0;
+
+	if (write_combine) {
+		if (arch_can_pci_mmap_wc() && (flags &
+		    (IORESOURCE_MEM | IORESOURCE_PREFETCH)) ==
+			(IORESOURCE_MEM | IORESOURCE_PREFETCH))
+			attr->mmap = pci_mmap_resource_wc;
+		else
+			return 0;
+	} else {
+		if (flags & IORESOURCE_MEM) {
+			attr->mmap = pci_mmap_resource_uc;
+		} else if (flags & IORESOURCE_IO) {
+			attr->read = pci_read_resource_io;
+			attr->write = pci_write_resource_io;
+			if (arch_can_pci_mmap_io())
+				attr->mmap = pci_mmap_resource_uc;
+		} else {
+			return 0;
+		}
+	}
+
+	attr->size = resource_size;
+	if (attr->mmap)
+		attr->f_mapping = iomem_get_mapping;
+
+	attr->private = (void *)(unsigned long)bar;
+
+	return attr->attr.mode;
+}
 #else /* !(defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)) */
 int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; }
 void __weak pci_remove_resource_files(struct pci_dev *dev) { return; }
-- 
2.32.0